Unreviewed, reverting 268760@main.

https://bugs.webkit.org/show_bug.cgi?id=263153

Seems to have introduced crashes on Apple Watch

Reverted changeset:

"Use StringView in CSSParserToken and simplify its code"
https://bugs.webkit.org/show_bug.cgi?id=262498
https://commits.webkit.org/268760@main

Canonical link: https://commits.webkit.org/269335@main

Source/WTF/wtf/text/StringView.cpp

@@ -261,15 +261,15 @@ String convertASCIICase(const CharacterType* input, unsigned length)
 String StringView::convertToASCIILowercase() const
 {
     if (m_is8Bit)
-        return convertASCIICase<ASCIICase::Lower>(static_cast<const LChar*>(m_characters.get()), m_length);
-    return convertASCIICase<ASCIICase::Lower>(static_cast<const UChar*>(m_characters.get()), m_length);
+        return convertASCIICase<ASCIICase::Lower>(static_cast<const LChar*>(m_characters), m_length);
+    return convertASCIICase<ASCIICase::Lower>(static_cast<const UChar*>(m_characters), m_length);
 }
 
 String StringView::convertToASCIIUppercase() const
 {
     if (m_is8Bit)
-        return convertASCIICase<ASCIICase::Upper>(static_cast<const LChar*>(m_characters.get()), m_length);
-    return convertASCIICase<ASCIICase::Upper>(static_cast<const UChar*>(m_characters.get()), m_length);
+        return convertASCIICase<ASCIICase::Upper>(static_cast<const LChar*>(m_characters), m_length);
+    return convertASCIICase<ASCIICase::Upper>(static_cast<const UChar*>(m_characters), m_length);
 }
 
 template<typename CharacterType>

Source/WTF/wtf/text/StringView.h

@@ -28,7 +28,6 @@
 #include <limits.h>
 #include <unicode/utypes.h>
 #include <wtf/Forward.h>
-#include <wtf/Packed.h>
 #include <wtf/RetainPtr.h>
 #include <wtf/Vector.h>
 #include <wtf/text/ASCIILiteral.h>
@@ -68,6 +67,7 @@ class StringView final {
     StringView(const LChar*, unsigned length);
     StringView(const UChar*, unsigned length);
     StringView(const char*, unsigned length);
+    StringView(const void*, unsigned length, bool is8bit);
     StringView(ASCIILiteral);
     ALWAYS_INLINE StringView(std::span<const LChar> characters) : StringView(characters.data(), characters.size()) { }
     ALWAYS_INLINE StringView(std::span<const UChar> characters) : StringView(characters.data(), characters.size()) { }
@@ -95,6 +95,7 @@ class StringView final {
     bool is8Bit() const;
     const LChar* characters8() const;
     const UChar* characters16() const;
+    const void* rawCharacters() const { return m_characters; }
     std::span<const LChar> span8() const { return { characters8(), length() }; }
     std::span<const UChar> span16() const { return { characters16(), length() }; }
 
@@ -229,13 +230,13 @@ class StringView final {
 
     void clear();
 
+    const void* m_characters { nullptr };
+    unsigned m_length { 0 };
+    bool m_is8Bit { true };
+
 #if CHECK_STRINGVIEW_LIFETIME
     UnderlyingString* m_underlyingString { nullptr };
 #endif
-
-    PackedPtr<const void> m_characters;
-    bool m_is8Bit { true };
-    unsigned m_length { 0 };
 };
 
 template<typename CharacterType, size_t inlineCapacity> void append(Vector<CharacterType, inlineCapacity>&, StringView);
@@ -309,8 +310,8 @@ inline StringView::~StringView()
 
 inline StringView::StringView(StringView&& other)
     : m_characters(other.m_characters)
-    , m_is8Bit(other.m_is8Bit)
     , m_length(other.m_length)
+    , m_is8Bit(other.m_is8Bit)
 {
     ASSERT(other.underlyingStringIsValid());
 
@@ -322,8 +323,8 @@ inline StringView::StringView(StringView&& other)
 
 inline StringView::StringView(const StringView& other)
     : m_characters(other.m_characters)
-    , m_is8Bit(other.m_is8Bit)
     , m_length(other.m_length)
+    , m_is8Bit(other.m_is8Bit)
 {
     ASSERT(other.underlyingStringIsValid());
 
@@ -395,6 +396,13 @@ inline StringView::StringView(const char* characters, unsigned length)
     initialize(reinterpret_cast<const LChar*>(characters), length);
 }
 
+inline StringView::StringView(const void* characters, unsigned length, bool is8bit)
+    : m_characters(characters)
+    , m_length(length)
+    , m_is8Bit(is8bit)
+{
+}
+
 inline StringView::StringView(ASCIILiteral string)
 {
     initialize(string.characters8(), string.length());
@@ -451,14 +459,14 @@ inline const LChar* StringView::characters8() const
 {
     ASSERT(is8Bit());
     ASSERT(underlyingStringIsValid());
-    return static_cast<const LChar*>(m_characters.get());
+    return static_cast<const LChar*>(m_characters);
 }
 
 inline const UChar* StringView::characters16() const
 {
     ASSERT(!is8Bit() || isEmpty());
     ASSERT(underlyingStringIsValid());
-    return static_cast<const UChar*>(m_characters.get());
+    return static_cast<const UChar*>(m_characters);
 }
 
 inline unsigned StringView::hash() const

Source/WebCore/css/CSSVariableData.cpp

@@ -48,7 +48,7 @@ template<typename CharacterType> void CSSVariableData::updateBackingStringsInTok
         if (!token.hasStringBacking())
             continue;
         unsigned length = token.value().length();
-        token.updateString({ currentOffset, length });
+        token.updateCharacters(currentOffset, length);
         currentOffset += length;
     }
     ASSERT(currentOffset == m_backingString.characters<CharacterType>() + m_backingString.length());

Source/WebCore/css/parser/CSSParserToken.cpp

@@ -41,14 +41,6 @@
 namespace WebCore {
 DEFINE_ALLOCATOR_WITH_HEAP_IDENTIFIER(CSSParserToken);
 
-struct SameSizeAsCSSParserToken {
-    StringView value;
-    unsigned flags;
-    double unionValue;
-};
-
-static_assert(sizeof(CSSParserToken) == sizeof(SameSizeAsCSSParserToken), "CSSParserToken should stay small");
-
 template<typename CharacterType>
 CSSUnitType cssPrimitiveValueUnitFromTrie(const CharacterType* data, unsigned length)
 {
@@ -377,30 +369,30 @@ CSSParserToken::CSSParserToken(CSSParserTokenType type, UChar c)
 }
 
 CSSParserToken::CSSParserToken(CSSParserTokenType type, StringView value, BlockType blockType)
-    : m_value(value)
-    , m_type(type)
+    : m_type(type)
     , m_blockType(blockType)
 {
+    initValueFromStringView(value);
     m_id = -1;
 }
 
 CSSParserToken::CSSParserToken(double numericValue, NumericValueType numericValueType, NumericSign sign, StringView originalText)
-    : m_value(originalText)
-    , m_type(NumberToken)
+    : m_type(NumberToken)
     , m_blockType(NotBlock)
     , m_numericValueType(numericValueType)
     , m_numericSign(sign)
     , m_unit(static_cast<unsigned>(CSSUnitType::CSS_NUMBER))
     , m_numericValue(numericValue)
 {
+    initValueFromStringView(originalText);
 }
 
 CSSParserToken::CSSParserToken(HashTokenType type, StringView value)
-    : m_value(value)
-    , m_type(HashToken)
+    : m_type(HashToken)
     , m_blockType(NotBlock)
     , m_hashTokenType(type)
 {
+    initValueFromStringView(value);
 }
 
 static StringView mergeIfAdjacent(StringView a, StringView b)
@@ -430,7 +422,7 @@ void CSSParserToken::convertToDimensionWithUnit(StringView unit)
     m_type = DimensionToken;
     m_unit = static_cast<unsigned>(stringToUnitType(unit));
     m_nonUnitPrefixLength = string == unit ? 0 : originalNumberTextLength;
-    m_value = string;
+    initValueFromStringView(string);
 }
 
 void CSSParserToken::convertToPercentage()
@@ -548,7 +540,7 @@ CSSParserToken CSSParserToken::copyWithUpdatedString(StringView string) const
 {
     ASSERT(value() == string);
     CSSParserToken copy(*this);
-    copy.m_value = string;
+    copy.initValueFromStringView(string);
     return copy;
 }
 

Source/WebCore/css/parser/CSSParserToken.h

@@ -117,7 +117,7 @@ class CSSParserToken {
     void convertToPercentage();
 
     CSSParserTokenType type() const { return static_cast<CSSParserTokenType>(m_type); }
-    StringView value() const { return m_value; }
+    StringView value() const { return { m_valueDataCharRaw, m_valueLength, m_valueIs8Bit }; }
 
     UChar delimiter() const;
     NumericSign numericSign() const;
@@ -137,19 +137,31 @@ class CSSParserToken {
 
     void serialize(StringBuilder&, const CSSParserToken* nextToken = nullptr) const;
 
-    void updateString(StringView string) { m_value = string; }
+    template<typename CharacterType>
+    void updateCharacters(const CharacterType* characters, unsigned length);
+
     CSSParserToken copyWithUpdatedString(StringView) const;
 
 private:
-    StringView m_value;
-
+    void initValueFromStringView(StringView string)
+    {
+        m_valueLength = string.length();
+        m_valueIs8Bit = string.is8Bit();
+        m_valueDataCharRaw = string.rawCharacters();
+    }
     unsigned m_type : 6; // CSSParserTokenType
     unsigned m_blockType : 2; // BlockType
     unsigned m_numericValueType : 1; // NumericValueType
     unsigned m_numericSign : 2; // NumericSign
     unsigned m_unit : 7; // CSSUnitType
     unsigned m_nonUnitPrefixLength : 4; // Only for DimensionType, only needs to be long enough for UnicodeRange parsing.
 
+    // m_value... is an unpacked StringView so that we can pack it
+    // tightly with the rest of this object for a smaller object size.
+    bool m_valueIs8Bit : 1;
+    unsigned m_valueLength;
+    const void* m_valueDataCharRaw; // Either LChar* or UChar*.
+
     union {
         UChar m_delimiter;
         HashTokenType m_hashTokenType;
@@ -158,4 +170,12 @@ class CSSParserToken {
     };
 };
 
+template<typename CharacterType>
+inline void CSSParserToken::updateCharacters(const CharacterType* characters, unsigned length)
+{
+    m_valueLength = length;
+    m_valueIs8Bit = (sizeof(CharacterType) == 1);
+    m_valueDataCharRaw = characters;
+}
+
 } // namespace WebCore